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Posts posted by mr9v9


    Raspberry Pi doesn't support power state management. It's either powered on (power plugged in) or off (power unplugged). You can of course shut down the operating system, but this doesn't mean that the Pi no longer takes the power, because it still does.


    There are external projects that try to add this capability to the Pi. For example this one http://spellfoundry.com/products/sleepy-pi/ but the price is not very tempting. Also you still couldn't power on the Pi using USB version of Flirc with this extra board. You would need to buy Flirc-SE (Streacom Edition), which has extra pins to power on a PC from any power state.


    You need to analyze if it's worth the price. The Pi doesn't consume much power. According to FAQ on the RPi website it draws current from 0.7A to 1A on 5V. Lets assume that it is 1A. The Pi uses 5 watts of power. 5 W * 24 hours * 31 days = 3.7 kWh (kilowatthours). Lets round it up to 4kWh. I don't know what is the price of electric power where you live but I pay about 15 cents per 1kWh where I live. This means that I would pay about 60 cents per month for running the Raspberry Pi constantly. OK power supplies don't have a 100% efficiency, so lets make it even $1 per month.

    Now take the amount of cash you would need to spend on the hardware to make the power on/off work:

    External board - £30.83 =~ $47
    Flirc-SE (I couldn't find a price quickly so I'll assume normal Flirc price) - $23
    It sums up to $70 I'll leave out the shipping and taxes out for this calculation.
    Given the total cost of hardware divided by monthly cost of running Pi all the time (70/1) you get that you can run the Pi for 70 months (almost 6 years) all the time to get to the price point of buying hardware to not run it constantly :) (and remember I didn't include taxes and shipping costs). I don't know how often you use your Pi but assuming its at least a few hours per week the time to recover the cost of buying the hardware would be even longer than those calculated 70 months. I think that sometime in those 6 years of time you'll get some other hardware for your media center.


    I was waiting for an idea to pop up and noticed you mentioned ATXRaspi in another post, so i thought yeah it's possible, but the prices are *insane* for some of these solutions. I did manage to find this one that is very tempting, but wanted a second opinion first?

    I forgot to mention it's not about power savings for my device, but rather my NAS seems to not want to sleep with the pi constantly sending a keep alive making the hard disks spin.

    I still can't quite understand why they can't make something so simple without corrupting your card at the same time!

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